1. Field of the Invention
The instant invention relates to mixing and reactor equipment. More specifically the invention is directed to equipment for mixing and reacting one or more fluids. The invention finds application in single as well as multi-phase environments.
2. State of the Art
Many fluid processes benefit from efficient mixing. Nearly all conventional art mixing equipment, such as blenders, impellers, static mixers, and impinging devices, scale and intermingle the fluids to be mixed while the fluids are in actual contact with one another. This approach can result in the creation of a variety of inhomogenieties within the body of the fluid mixture. Such inhomogenieties may be harmful to the process of mixing and/or the reactions occurring within the body of the fluid. For example, large scale concentration or temperature inhomogenieties may be produced within the body of the fluid mixture by the use of conventional mixing equipment.
Additionally, conventional mixing equipment generally relies upon forcing large scale turbulence upon the fluid mixture. Turbulence, in turn, may lead to the formation of eddies within the fluid body which, in many instances, may be as large as the reaction vessel itself. The presence of eddies within the fluid body may hamper the proper mixing of the fluid and further may disrupt the extent of the reactions occurring within the fluid.
Historically, slight attention has been paid in the art to the use of engineered fractal mixing as a means of processing fluids. U.S. Pat. No. 5,938,333 is one of the few examples of technical efforts in this area. In U.S. Pat. No. 5,938,333 a space filling device, which can be used for low turbulence fluid mixing in a volume, is disclosed. This device can accomplish volume mixing with very little turbulence and with a high level of homogeneity. Unfortunately, because the device of U.S. Pat. No. 5,938,333 is a space filling mixer, it is not always an appropriate processing device for a given processing requirement.
Another recent patent which describes the use of fractals to distribute or collect fluids is U.S. Pat. No. 5,354,460 which discloses a fractal fluid distribution system. PCT/US99/06245 is directed to a fractal fluid transporting device. Neither of these references disclose employing offset fractals to simultaneously and independently scale and intermingle separate fluids for mixing and/or reaction.
The instant invention provides a method and apparatus for mixing or reacting a fluid mixture wherein one or more of the component fluids of the mixture are scaled and intermingled prior to their contacting another component fluid. Central to this method is the use of a structure which includes independent offset fluid transporting fractals. This new structure eliminates large scale eddies by scaling the entire flow of fluids through independent fractals prior to a mixing/reaction of the fluids. Furthermore, the present invention does not mix to a volume and thus the invention provides several new practical industrial opportunities for fractal mixing. This new structure scales and mixes fluid in a manner which is appropriate for flows exiting to or crossing an area (instead of a volume) and is not a space filling fractal configuration. We have discovered a number of useful applications which can use this different approach. An important example is the use of this device via attachment to a flow-through pipe. This allows simple but efficient pipe flow oriented fluid mixing and reaction. Using the structure in this manner is beneficial because it allows easy incorporation into existing processing technology. Another industrially useful application is attaching the device to the side of a vessel so that fluids are mixed homogeneously just prior to entering the vessel. Still another useful application is the provision of a surface of homogeneously mixed gases for subsequent combustion applications.
The instant invention is particularly applicable to providing rapid and homogeneous mixing, with or without a reaction occurring between the fluids. The invention can also provide controlled mixing and heat transfer simultaneously, for example in order to control the temperature of a reaction process. Contemplated uses of the invention include the following:
1. Mixing two or more fluids rapidly.
2. Mixing two or more fluids while controlling temperature.
3. Mixing and reacting two or more fluids.
4. Mixing and reacting two or more fluids while controlling temperature.
5. Mixing two or more fluids to allow subsequent homogeneous reaction outside the device.
Further environments wherein the invention may find application include the following:
1. Liquid-liquid mixers.
2. Gas-gas mixers.
3. Gas-liquid mixers.
4. Liquid-liquid reactors.
5. Gas-liquid reactors.
6. Gas-gas reactors.
7. Aerators.
8. Carbonators.
9. Fluid mixing prior to combustion.
By using the instant invention, two or more fluids can be rapidly mixed in a homogeneous manner without using mechanical mixing equipment. Turbulence inducing mechanical mixing devices, such as impellers, blenders, impinging devices, etc. are not used. Therefore large scale mixing inhomogeneities can be avoided. Large scale eddies in mixing processes can reduce the yield of chemical reactions. This device eliminates large scale eddies from the mixing process. Avoiding mechanical mixing can also reduce the amount of energy used. Ordinary mixing processes most commonly result in energy wasted because the large scale turbulence which is forced on the mixing process must eventually be dissipated as heat. The device in this invention does not form large scale turbulence or eddies so large scale motion is not dissipated as wasted energy.
The distribution of fluid properties can be controlled in a beneficial manner using the invention. For example, for a gas mixing with a liquid, the gas bubble size distribution can be controlled and at the same time the liquid is also scaled, therefore mass transfer characteristics are more controlled. Other fluid property distributions which can be controlled by this device include fluid velocities, temperature, concentration and eddy size.
Because fluid property distributions can be more controlled compared with conventional mixing/reactor equipment, the equipment can be smaller and more efficient. If desired, the mixing can be rapid and homogeneous but with very gentle treatment of the fluids. The various embodiments of the invention can be used as elements in conventional processing. For example, as a rapid mixer in an ordinary pipeline or as an multi-fluid mixer entering a tank or other vessel.
Unlike nearly all fluid reactors, the various components to be mixed and reacted can all be scaled and intermingled with one another prior to contact with one another. This results in a more rapid and homogeneous reaction. Side reactions caused by large scale inhomogenieties can be avoided. Furthermore, mixing and reaction temperature can easily be controlled. Large mixing or reactor tanks can be completely eliminated since all the fluids to be mixed and/or reacted can be scaled and intermingled together in this device.